The present invention relates to a receptacle connector, particularly to a receptacle connector having a drop-in structure that includes a peripheral shell with a counter connector accommodating portion formed therein and opening in a fitting direction.
In portable electronic devices such as mobile phones and smartphones, typically, a built-in antenna is disposed along an inner surface of a housing of an electronic device in order to have improved transmission and reception of radio waves; however, when a metal surface forming a ground pattern is present near the built-in antenna, even if the metal surface is situated further inside the housing than the built-in antenna, the transmission and reception characteristics of the built-in antenna may deteriorate due to the influence of the metal surface.
To cope with it, the measures in which a planar ground pattern is not formed on a substrate disposed near a built-in antenna have been taken to reduce the influence of a metal surface on the transmission and reception characteristics.
Meanwhile, in recent years, portable electronic devices are remarkably getting thinner, and accordingly, the thickness of a receptacle connector mounted on a substrate for connection with an external device makes up a large portion of the thickness of the associated electronic device.
To cope with it, in some cases, utilized is not a receptacle connector having a structure which allows the connector to be placed and mounted on a surface of a substrate but a receptacle connector having a so-called drop-in structure which allows mounting using a cutout formed in a substrate.
For example, CN 203859323 U discloses a receptacle connector 1 having the drop-in structure as shown in FIG. 10. The receptacle connector 1 has a metal shell 3 that opens frontward, covers the periphery of a plurality of contacts 2 and serves to introduce a plug connector which is a counter connector to be fitted. A substrate 4 on which the receptacle connector 1 is mounted is formed with a cutout 5. With the front part of the metal shell 3 being inserted in the cutout 5, soldering portions 6 of the metal shell 3 are soldered to the substrate 4, while the rear ends of the contacts 2 are soldered to connection pads (not shown) of the substrate 4, whereby the receptacle connector 1 is mounted.
Owing to the use of the receptacle connector 1 having the drop-in structure as above, a thinner electronic device can be formed as compared to the case where the receptacle connector 1 is placed and mounted on the surface of the substrate 4 without provision of the cutout 5.
As shown in FIG. 11, however, a bottom surface 3A of the metal shell 3 of the receptacle connector 1 is exposed on a bottom surface 4A side of the substrate 4 through the cutout 5; therefore, when this receptacle connector 1 having the drop-in structure is used in a thin electronic device, the bottom surface 3A of the metal shell 3 is situated close to the inner surface of a housing of the electronic device and acts as a metal surface, which may degrade the transmission and reception characteristics of a built-in antenna.
Since the metal shell 3 of the receptacle connector 1 introduces a plug connector which is a counter connector, the metal shell 3 needs to have a predetermined strength in order particularly to tackle so-called “twisting” in a fitting process, and in addition, it is desired to use a grounded metal component for an opening end of the metal shell 3, which end may be contacted from the outside of the housing of the electronic device, in order to discharge static electricity.